The present invention relates to structures upon which high current conductors may be deposited and methods for fabricating said structures, and more particularly to buffer layer architectures such as MgO/Ag/Pt/Ni, MgO/Ag/Pd/Ni, MgO/Ag/Ni, MgO/Ag/Pd/Cu, MgO/Ag/Pt/Cu, and MgO/Ag/Cu, MgO/Pt/Ni, MgO/Pd/Ni, MgO/Pt/Cu, and MgO/Pd/Cu.
It has long been desired to grow biaxially oriented oxide buffer layers other than CeO2 directly on textured-Ni substrates. Also it has been desired to provide an alternative to pulsed laser deposition processes that may be easier to scale up for producing thick buffer layers.
Recent developments in deposited conductors, both rolling assisted biaxially textured substrates (RABiTS), and ion-beam assisted deposition (IBAD) based on YBa2Cu3O7 superconductors are promising, especially superconductors deposited on buffered substrates.
The xe2x80x9cdeposited conductorxe2x80x9d approach described herein is useful for growing superconductors such as REBa2Cu3O7, (Bi,Pb)2Sr2Canxe2x88x921CunO2n+4 (n=1-3), Tl1Ba2Canxe2x88x921CunO2n+3(n=1-4), Tl2Ba2Canxe2x88x921CunO2n+4(n=1-3), and Hg1Ba2Canxe2x88x921CunO2n+2+xcex2(n=1-4) with high critical-current densities. These high Jc conductors will be suitable for transmission lines and various other applications.
This invention opens up a wide variety of possibilities of growing several other buffer layers such as SrTiO3, LaAlO3, REAlO3 (RE=Rare Earth), BaZrO3, and CaZrO3 on either buffered-rolled metal substrates or directly on rolled metal substrates. The demonstrated buffer layers may also be useful for photovoltaics, ferroelectrics, sensors, and electro-optic applications The following sections of publications also relate to the present invention, and are hereby incorporated by reference:
X. D. Wu, S. R. Foltyn, P. Arendt, J. Townsend, C. Adams, I. H. Campbell, P. Tiwari, Y. Coulter, and D. E. Peterson, Appl. Phys. Lett. 65 (15), Oct. 10, 1994, p1961.
M. Paranthaman et al., Physica C 275 (1997) 266-272.
C. Prouteau, J. F. Hamet, B. Mercery, M. Hervieu, B. Raveau, D. Robbes, L. Coudrier, and G. Ben, xe2x80x9cSignificant improvement of superconductivity of laser ablated YBa2Cu3O7/MgOxe2x80x9d thin films: Introduction of a SrTiO3 buffer layer,xe2x80x9d Physica C, Vol. 248, 108-118 (1995)
Chunyan Tian, Yang Du, and Siu-Wai Chan: xe2x80x9cEpitaxial formation and characterization of CeO2 films.xe2x80x9d MRS proceeding Vol 355 on Evolution of Thin Film and Surface Structure and Morphology edited by B. G. Demczyk, E. D. Williams, E. Gatfunkel, B. M. Clemens, J. J. Cuomo, 1995. ISDN: 155899-256-1.
Wei-Yung Hsu, and Rishi Raj: xe2x80x9cMgO epitaxial thin films on (100) GaAs as a substrate for the growth of oriented PbTiO3,xe2x80x9d Appl. Phys. Lett., Vol. 60, June 1992, pp.3105-3107.
Accordingly, it is an object of the present invention to provide new and improved biaxially oriented MgO buffer layers on textured substrates comprising Ni.
It is another object to provide an alternative to pulsed laser deposition processes that may be easier to scale up for producing thick buffer layers.
Further and other objects will become apparent from the description contained herein.
In accordance with one aspect of the present invention, the foregoing and other objects are achieved by a biaxially textured article which comprises: a substrate which comprises at least one metal selected from the group consisting of Ni and Cu, the substrate having a surface exhibiting biaxial texture; a first buffer layer selected from the group consisting of Pd and Pt, the first buffer layer being epitaxially disposed upon the biaxially-textured surface of the Ni; a second buffer layer which comprises Ag, the second buffer layer being epitaxially disposed upon the biaxially textured surface of the first buffer layer; and a third buffer layer which comprises MgO epitaxially disposed upon the biaxially textured surface of the Ag.
In accordance with a second aspect of the present invention, the foregoing and other objects are achieved by a method for making a biaxially textured article which comprises the steps of: providing a substrate which comprises at least one metal selected from the group consisting of Ni and Cu, the substrate having a surface exhibiting biaxial texture; epitaxially depositing upon the biaxially textured surface of the Ni a first buffer layer selected from the group consisting of Pd and Pt; epitaxially depositing upon the biaxially textured surface of the first buffer layer a second buffer layer comprising Ag; and epitaxially depositing upon the biaxially textured surface of the Ag a third buffer layer comprising MgO.
In accordance with a third aspect of the present invention, the foregoing and other objects are achieved by a biaxially textured article which comprises: a substrate which comprises at least one metal selected from the group consisting of Ni and Cu, the substrate having a surface exhibiting biaxial texture; a first buffer layer which comprises Ag, the first buffer layer being epitaxially disposed upon the biaxially textured surface of the substrate; and a second buffer layer which comprises MgO epitaxially disposed upon the biaxially textured surface of the Ag.
In accordance with a fourth aspect of the present invention, the foregoing and other objects are achieved by a method for making a biaxially textured article which comprises the steps of: providing a substrate which comprises at least one metal selected from the group consisting of Ni and Cu, the substrate having a surface exhibiting biaxial texture; epitaxially depositing upon the biaxially textured surface of the substrate a first buffer layer which comprises Ag; and epitaxially depositing upon the biaxially textured surface of the Ag a second buffer layer which comprises MgO.